It probably won't matter even if you did learn German. The dog remembers it's masters voice in German. So you would have to mimic him and speak German.
Dogs don't actually learn words but sounds. So you must "master" the dog.
Going first outside the door, loose leash walking, coming when called, sitting for treat. etc.
A good way to teach a dog that "Hey, I'm above you in this pack!".
Is to lay the dog down holding it's scruff until the dog stops wiggling. Dogs do this in nature to show dominance. Soon the dog will actually roll over onto her belly when you walk over. (Showing belly is a sign of submitting).
Once you have mastered the dog, THEN you can teach the dog it's name.
Teach your dog that you know her language (not German). But Dog.
Start by doing some simple No commands. (No... Don't say No.).
Say this "AH! AH!" sounds sorta like this "A-EH! A-EH!". Loud and quick. Dogs actually make a grunt like this noise to show a sign of "No", "Don't want to", "leave me alone". Remember. Master the dog.
Once doing all this (weeks, maybe months). You can teach any command you like. Even change her name.
You must make the dog want to follow you, not to follow the treat.